src/com/android/launcher3/widget/picker/WidgetsListAdapter.java

/*
 * Copyright (C) 2015 The Android Open Source Project
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *      http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */
package com.android.launcher3.widget.picker;

import android.content.Context;
import android.util.Log;
import android.util.SparseArray;
import android.view.LayoutInflater;
import android.view.View;
import android.view.View.OnClickListener;
import android.view.View.OnLongClickListener;
import android.view.ViewGroup;

import androidx.recyclerview.widget.RecyclerView;
import androidx.recyclerview.widget.RecyclerView.Adapter;
import androidx.recyclerview.widget.RecyclerView.ViewHolder;

import com.android.launcher3.R;
import com.android.launcher3.WidgetPreviewLoader;
import com.android.launcher3.icons.IconCache;
import com.android.launcher3.recyclerview.ViewHolderBinder;
import com.android.launcher3.util.LabelComparator;
import com.android.launcher3.widget.WidgetCell;
import com.android.launcher3.widget.model.WidgetsListBaseEntry;
import com.android.launcher3.widget.model.WidgetsListContentEntry;

import java.util.ArrayList;
import java.util.Collections;
import java.util.Comparator;
import java.util.List;

/**
 * List view adapter for the widget tray.
 *
 * <p>Memory vs. Performance:
 * The less number of types of views are inserted into a {@link RecyclerView}, the more recycling
 * happens and less memory is consumed.
 */
public class WidgetsListAdapter extends Adapter<ViewHolder> {

    private static final String TAG = "WidgetsListAdapter";
    private static final boolean DEBUG = false;

    /** Uniquely identifies widgets list view type within the app. */
    private static final int VIEW_TYPE_WIDGETS_LIST = R.layout.widgets_list_row_view;

    private final WidgetsDiffReporter mDiffReporter;
    private final SparseArray<ViewHolderBinder> mViewHolderBinders = new SparseArray<>();
    private final WidgetsListRowViewHolderBinder mWidgetsListRowViewHolderBinder;

    private ArrayList<WidgetsListBaseEntry> mEntries = new ArrayList<>();

    public WidgetsListAdapter(Context context, LayoutInflater layoutInflater,
            WidgetPreviewLoader widgetPreviewLoader, IconCache iconCache,
            OnClickListener iconClickListener, OnLongClickListener iconLongClickListener) {
        mDiffReporter = new WidgetsDiffReporter(iconCache, this);
        mWidgetsListRowViewHolderBinder = new WidgetsListRowViewHolderBinder(context,
                layoutInflater, iconClickListener, iconLongClickListener, widgetPreviewLoader);
        mViewHolderBinders.put(VIEW_TYPE_WIDGETS_LIST, mWidgetsListRowViewHolderBinder);
    }

    /**
     * Defers applying bitmap on all the {@link WidgetCell} in the {@param rv}.
     *
     * @see WidgetCell#setApplyBitmapDeferred(boolean)
     */
    public void setApplyBitmapDeferred(boolean isDeferred, RecyclerView rv) {
        mWidgetsListRowViewHolderBinder.setApplyBitmapDeferred(isDeferred);

        for (int i = rv.getChildCount() - 1; i >= 0; i--) {
            ViewHolder viewHolder = rv.getChildViewHolder(rv.getChildAt(i));
            if (viewHolder.getItemViewType() == VIEW_TYPE_WIDGETS_LIST) {
                WidgetsRowViewHolder holder = (WidgetsRowViewHolder) viewHolder;
                for (int j = holder.cellContainer.getChildCount() - 1; j >= 0; j--) {
                    View v = holder.cellContainer.getChildAt(j);
                    if (v instanceof WidgetCell) {
                        ((WidgetCell) v).setApplyBitmapDeferred(isDeferred);
                    }
                }
            }
        }
    }

    @Override
    public int getItemCount() {
        return mEntries.size();
    }

    /** Gets the section name for {@link com.android.launcher3.views.RecyclerViewFastScroller}. */
    public String getSectionName(int pos) {
        return mEntries.get(pos).mTitleSectionName;
    }

    /** Updates the widget list. */
    public void setWidgets(List<WidgetsListBaseEntry> tempEntries) {
        ArrayList<WidgetsListBaseEntry> newEntries = new ArrayList<>(tempEntries);
        WidgetListBaseRowEntryComparator rowComparator = new WidgetListBaseRowEntryComparator();
        Collections.sort(newEntries, rowComparator);
        mDiffReporter.process(mEntries, newEntries, rowComparator);
    }

    @Override
    public void onBindViewHolder(ViewHolder holder, int pos) {
        ViewHolderBinder viewHolderBinder = mViewHolderBinders.get(getItemViewType(pos));
        viewHolderBinder.bindViewHolder(holder, mEntries.get(pos));
    }

    @Override
    public ViewHolder onCreateViewHolder(ViewGroup parent, int viewType) {
        if (DEBUG) {
            Log.v(TAG, "\nonCreateViewHolder");
        }

        return mViewHolderBinders.get(viewType).newViewHolder(parent);
    }

    @Override
    public void onViewRecycled(ViewHolder holder) {
        mViewHolderBinders.get(holder.getItemViewType()).unbindViewHolder(holder);
    }

    @Override
    public boolean onFailedToRecycleView(ViewHolder holder) {
        // If child views are animating, then the RecyclerView may choose not to recycle the view,
        // causing extraneous onCreateViewHolder() calls.  It is safe in this case to continue
        // recycling this view, and take care in onViewRecycled() to cancel any existing
        // animations.
        return true;
    }

    @Override
    public long getItemId(int pos) {
        return pos;
    }

    @Override
    public int getItemViewType(int pos) {
        WidgetsListBaseEntry entry = mEntries.get(pos);
        if (entry instanceof WidgetsListContentEntry) {
            return VIEW_TYPE_WIDGETS_LIST;
        }
        throw new UnsupportedOperationException("ViewHolderBinder not found for " + entry);
    }

    /** Comparator for sorting WidgetListRowEntry based on package title. */
    public static class WidgetListBaseRowEntryComparator implements
            Comparator<WidgetsListBaseEntry> {

        private final LabelComparator mComparator = new LabelComparator();

        @Override
        public int compare(WidgetsListBaseEntry a, WidgetsListBaseEntry b) {
            return mComparator.compare(a.mPkgItem.title.toString(), b.mPkgItem.title.toString());
        }
    }
}